8 7
6+
5
4 3
N
1
-8 -7 -6 -5 4ß -2
-1
1
2 3 4 5 6 7 8
-2
-3
-5
-6
-7
-8+
The system of equations has
O one solution
no solution
infinitely many solutions

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.